i) Field of the Invention
This invention relates to pressure measuring devices and in particular to devices suitable for measuring the output characteristics of a CPAP blower.
ii) Summary of the Prior Art
Breathing circuits have been known for some time incorporating in line humidification devices. A common form of humidification device includes a water containing humidification chamber fitted to a heater base. Gases flowing through the humidification chamber are humidified from the heated water reservoir therein. Breathing circuits of this type have been used in artificial or assisted ventilation systems.
More recently such humidification systems have been adopted in CPAP treatment of obstructive sleep apnea. Devices such as the HC200 (available form the applicant) integrate the CPAP blower and the humidifier heater base. The chamber slides onto the heater base and accomplishes simultaneous connection with the outlet of the CPAP blower. A humidification chamber for use with such a machine is depicted in FIG. 3.
For the comfort of the user it is desirable from time to time to check and/or adjust the pressure provide by the CPAP blower.
It is an object of the present invention to provide a measuring device which goes some way to meeting the above desiderata or which will at least provide users with a useful choice.
In a first aspect the invention consists in a measuring device comprising:
A connector formed to connect with the outlet of a humidification chamber,
a calibrated tube extending through said connector to be retained in an at least substantially vertical direction through a said outlet with said connector fitted to the said outlet, and
a bias flow outlet through said connector.
In a still further aspect the invention consists in a method of assessing the operation of a CPAP blower comprising:
filling a water chamber to a level,
connecting said chamber to said CPAP blower,
fitting a connector having an orifice therethrough, a calibrated tube passing through said orifice, and a gases flow bypass of predetermined flow constraint, to the outlet of the water chamber.
adjusting the position of said tube through said connector such that a predetermined point on said tube aligns with the level of said water within said chamber,
activating said CPAP blower,
waiting for the liquid level in said tube to reach a stable position, and
assessing performance of the CPAP blower by comparing the attained level of said water in said tube with a desired level.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.